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EPA Releases Final Risk Evaluation for 1,4-Dioxane

For Release: December 31, 2020

Today, the U.S. Environmental Protection Agency (EPA) released the final risk evaluation for 1,4-dioxane. Under the Toxic Substances Control Act (TSCA), EPA is required to evaluate the risks associated with exposure to existing chemicals in commerce using the best available science and then take action to address any unreasonable risk identified. Today’s final risk findings complete the final risk evaluation required by TSCA for 1,4-dioxane.

EPA used feedback received during the public comment period and the scientific peer review process carried out by the Science Advisory Committee on Chemicals to inform the final risk evaluation. The final risk evaluation for 1,4-dioxane identifies unreasonable risk to workers for 13 out of 24 conditions of use. EPA found no unreasonable risk to the general population, occupational non-users, and the environment. The Agency also published a supplemental analysis to the draft risk evaluation that evaluated eight additional conditions of use for 1,4-dioxane present as a by-product in consumer products. After carefully considering public comment on the supplemental analysis, the final risk evaluation found no unreasonable risk for these consumer uses.

The next step in the process required by TSCA is to address the unreasonable risk identified in the final risk evaluation. EPA is now moving immediately to risk management for 1,4-dioxane. The Agency will work as quickly as possible to propose and finalize actions to protect against unreasonable risk. Potential actions EPA could take include regulation of how these chemicals are used, limiting or prohibiting the manufacture, processing, distribution in the marketplace, use, or disposal of these chemicals, as applicable.

As with any chemical product, EPA strongly recommends that users of products containing 1,4-dioxane continue to carefully follow all instructions on a product’s label and safety data sheets.

View the final risk evaluation and supporting documents for 1,4-dioxane.


1,4-dioxane is used primarily as a solvent in a variety of commercial and industrial applications including in the manufacture of other chemicals, as a processing aid, as a laboratory chemical, and in adhesives and sealants. 1,4-dioxane may be found as a by-product in consumer products such as soaps and detergents. EPA did not identify any direct consumer uses of this chemical.

Learn more about the risk evaluation process required by TSCA: